1. Field of the Invention
This invention relates generally to a fenestration unit which does not include an insulated glass unit (IGU). More specifically, the glass panes are placed directly into the sash without first being permanently fastened to each other by a spacer. This invention also includes a method for manufacturing a fenestration unit without the utilization of an IGU.
2. Description of the Prior Art
Early fenestration units, including windows and doors, only had a single pane of glass. Typically, the glass would be placed in the sash and then a glazing material would be applied to hold the glass into the sash. However, in more recent times, two or more panes of glass have been utilized in windows for better insulating value. A gap between any two glass panes creates further insulation. The prior art teaches the use of a separate spacer between the two glass panes to create such a gap and to structurally support the two panes of glass.
FIG. 1 illustrates a typical IGU 10 of the prior art. A first glass pane 11 is sealed to one end of spacer 12 with a sealant 14, and a second glass pane 16 is sealed to the other end of spacer 12 with sealant 14. The spacer 12 can be of many different shapes but often it is made with a jagged edge as shown in FIG. 1 to reduce the conductance of heat through the spacer. This combination of two or more glass panes separated by a spacer is manufactured as a unit (IGU 10) and then later placed into the sash of the fenestration unit.
FIG. 2 illustrates the IGU 10 after it has been placed in the sash 17 of a fenestration unit.
The prior art fenestration units have a number of problems. Manufacturing involves two operations in which the first operation is manufacturing the IGU and the second operation is placing the IGU in the sash. This dual operation process incorporates significant cost into the fenestration unit. Additionally, this dual operation process typically involves shipping glass from the glass factory to the window manufacturer in the form of an IGU. Such shipping involves greater cost because the IGU's take up more space and they are easier to break than individual glass panes. Additionally, despite efforts to minimize thermal conductivity through the spacer 12, there continues to be significant heat loss through the spacer 12.